This invention relates to a signal delay connector for a blasting signal detonating cord.
In detonating a plurality of blasting charges it is often required that the timing of such detonations be controlled precisely. This is true, for example, in blasting quarries where sequential delays between charges must be controlled within milliseconds. In order to control such timing of charges, transmission lines are deployed from a central initiating point to send a signal to detonate the individual blasting charges. Normally, these lines consist of one or more main truck lines connected to a plurality of down lines.
Timing of the detonating signal is normally accomplished by using preselected lengths of known signal velocity transmission lines, and by utilizing signal delay units where necessary.
The manner of connection of the signal transmission lines, for example, between a trunk line and a plurality of down lines, depends on the type of transmission line utilized. Conventional destructing combustible fuses and detonating cords may be connected by tying together and knotting the line ends. In some cases supplementary charges are utilized to assure that the signal is transmitted. A supplementary charge device is as disclosed in U.S. Pat. No. 4,481,884. Where additional delay time is required, a delay unit may be tied between the ends of the combustible fuses or detonating cords, for example, as disclosed in U.S. Pat. No. 2,736,263.
It is often desired to insert a signal delay unit in an intermediate portion of a detonating cord between the cord ends. With prior art delay units, it is necessary to cut the detonating cord at the desired insertion point and then secure the ends, usually by tying, to a signal delay unit. This can be a time-consuming process. Problems may also develop with the amount of cord available for securing the cord ends to the delay unit. It is almost always difficult, or at least inconvenient, to cut the detonating cord itself because of the additional tools required.
Even if it is desired to secure a delay unit between already separate detonating cord ends, problems can arise with the reliability of the connections between the cord and the unit. Knots may be difficult to make in the detonating cord during field installation. Care must be taken to position the input and output detonating cords on either side of the signal delay unit so that they do not touch to prevent a signal from passing from the input cord directly to the output cord and bypassing the delay unit. Furthermore, restraints on detontaing cord coreload are often imposed to prevent "sympathetic" or instaneous initiation of the delay explosive train and the output cord.
Blasting operations almost always take place in outdoor or underground locations. All of the above stated problems are compounded where such activities take place under adverse environmetal circumstances such as in rain, snow or cold conditions.
It is therefore an object of the present invention to provide an improved means for connecting a signal delay unit to detonating cord which does not require tying or knotting.
It is another object of the present invention to provide a means for connecting a signal delay unit to detonating cord which has improved reliability.
It is a further object of the present invention to provide a means for connecting a signal delay unit to detonating cord which may be utilized under adverse environmental conditions.
It is another object of the present invention to provide a means for connecting a signal delay unit to a detonating cord at an intermediate portion thereof.
It is yet another object of the present invention to provide a means for connecting a signal delay unit to detonating cord which requires no additional tools.
It is a further object of the present invention to provide a means for connecting a signal delay unit to detonating cord which is inexpensive and essentially disposable.
Other objects will be in part obvious and in part pointed out in more detail hereinafter.
A better understanding of the objects, advantages, features, properties and relations of the invention will be obtained from the following detailed description and accompanying drawing which sets forth an illustrative embodiment and is indicative of the way in which the principle of the invention is employed.